2025-02-13_REVISION - M2020007 (6)

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EXHIBIT G WATER INFORMATION(CONT) influence the groundwater levels and impact the baseline range and trigger point . The natural groundwater depths vary from 3 . 5 to 8 . 8 feet below the surface in Phases 1 and 2 when they were measured in March-2019 . The seasonal operation of the unlined irrigation return flow ditch that crosses the permit area on the west will affect groundwater levels and could help with any mitigation needs in the Phases west of the highway. An Underdrain was installed along the northeast side of Phase 1 and the southeast side of Phase 2 at the request of the Landowner. The underdrain is shown on all amended Map Exhibits . The underdrain starts in two places - along the southeast side of Phase 2, and along the northeast side of Phase 1 . The two sections connect and the underdrain continues between the north slurry wall of Phase 1 and the south slurry wall of Phase 2 . The outlet of the underdrain is past the west side of the phases, near the river. The underdrain design and hydrologic evaluation information is included in the APPENDIX. The underdrain maintains the hydrologic balance and maintains the groundwater elevation outside the slurry wall at its historic levels, by allowing the groundwater to seep into and through the underdrain. There are clean out and inspection hatches located on the surface above the underdrain pipe at regular intervals to facilitate maintenance by the reservoir owners (Cannon Land Co. ) . Between the Platteville Ditch and the Railroad in Phases 4, 5, & 6, the groundwater depth varies from 3 to 24 feet below the surface, when measured in March 2019 . Groundwater depths can vary significantly through seasons and years, depending on many influences, including, climate, precipitation, irrigation, other pumping rights, and much more. L.G. Everist, Ines . experience on other mines in the South Platte River valley indicates that groundwater levels can fluctuate as much as 7+ feet depending on the season. In a normal mitigation trigger plan, the trigger limits would be set at 3 foot change plus or minus change over a 3-month average. Realistically, in this case the trigger number should be based on a 3-foot change determined by a line that approximates a up or downward trend of the water table and considers outside impacts such as, drought, adjoining mining activities, storm events or decreased irrigation activities . We do not expect this to be a problem where the slurry walls are in close proximity to a flowing water body like the ditches, return flow ditch and the South Platte River. Mounding would be controlled by those water surfaces and it would only affect Cannon Land Company areas around the reservoirs . On the east side of the Platte Valley Canal, the ground-water table averages 11 feet deep and there are L.G. Everist, Inc. Ragsdale Reservoirs Revised February 11, 2025 37